There exists an abundance of software packages for Riemannian optimization. The most popular choice, offering a wide variety of Riemannian optimization algorithms and a user-friendly environment in MATLAB, is Manopt [1]}. A more recent library for manifold optimization is ROPTLIB [2]}. Most of the kernels in ROPTLIB are written in C++ and use the highly optimized BLAS and LAPACK libraries for efficient linear algebra operations.
We utilize the MATLAB interface of the ROPTLIB package for the solution of our Grassmann minimization problem (REF ), due to the state-of-the-art Newton method implemented in it and its superiority in terms of computational runtimes [2]}.
